<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>行元素</title>
    <style>
        /* 不会影响到div */
        .span1 {
            font-size: 30px;
            background-color: red;
            /* margin没有向下挤div */
            margin: 100px;
        }

        .div1 {
            width: 200px;
            height: 200px;
            background-color: blue;
        }
    </style>
</head>

<body>

    <span class="span1">我是行内元素span</span>
    <div class="div1">
    </div>

</body>

</html>